January 28, 2018

Talking Heads

If you point at something and say to your dog, “Hey, look
over there!” the dog will look at your finger. If you show your dog a picture
of a steak, the dog will sniff the paper and lose interest. And if you talk to
your dog, the dog will enjoy the conversation, but it won’t really understand
what you’re talking about. Dogs don’t “get” symbols.

A symbol is something that
means something else. Symbols take the form of words, gestures, pictures, or
meaningful objects. Apes and dolphins have only a limited capacity for using
symbols, and other non-human animals seem to have none at all. Something
happened to our ancestors that didn’t happen to theirs.

Around ten million
years ago the earth’s climate began to grow cooler and dryer, causing the dense
tropical forest that covered Africa to recede, leaving expanses of grassland in
its place. Without the protective safety of the trees, some primates made a go
of life among the big cats and other predators on the open plains. Some of them
were able to stand on their hind legs, a trait favored by natural selection
because it helped them see farther and detect danger sooner. Over time hominids
began to walk on two legs, freeing their hands to pick up sticks and stones to
use as weapons or tools.

Natural selection began to
place a hefty premium on intelligence—not just any intelligence, but the kind
of communicative intelligence that makes people effective in social groups.
Even back then, some individuals would have been more articulate than others.
Their gestures and speech-like grunts might have been easier to understand or
might have expressed a richer vocabulary of thought. They would have been
better at warning of danger, communicating the location of food, and
coordinating group activities in hunting and battle. They would have been
better parents. They would have been more attractive and seductive to potential
mates. For possibly all of these reasons, natural selection favored the genes
and brains of those with the gift of gab.

There must have
been moments when language suddenly became capable of doing things it had never
done before. There must have been a first verb, a first sentence, a first
question. It’s hard to say exactly when or how this happened. Prehistory is a
tale told in stones and bones, and the first words left no traces of
themselves. Most estimates place the origin of language sometime between
200,000 and 50,000 years ago—between the time of the first Homo sapiens and the advent of behaviorally modern humans.

The stones and
bones suggest that for hundreds of thousands of years, advances in human
cognition were slow. The skulls show a small gradual increase in brain size.
But the stone tools—simple sharpened rocks of generic design—stayed more or
less the same. Then something happened.
Around 100,000 years ago there was a sudden blossoming of human culture. This
cognitive revolution could have been the culmination of many thousands of years
of gradual evolutionary changes to the brain and larynx. It could have been
that the survival pressures of the Ice Age placed an even greater premium on
intelligence. It could have been some powerful new feature of grammar, such as
the ability to express thoughts about thoughts. For whatever reasons, human
artifacts grew more advanced. The stone blades show evidence of more
sophisticated sharpening techniques. Some artifacts show clear evidence that
people were thinking in terms of symbols.

The oldest
surviving symbols are beads, some of which are about 80,000 years old.
Prehistoric beads are typically seashells with holes drilled through them.
Beads are often found in burial sites, which suggests their function was
somehow symbolic. Beads “said something” about the status and social role the
person wearing them, in much the same way that a modern wedding ring says
something about the person wearing it.

At a rock shelter
in France named Abri de Cro-Magnon and at similar sites throughout
Europe, archaeologists have found artifacts of a remarkably advanced human
culture from about 30,000 years ago. These Cro-Magnon humans used flaking
techniques to produce sharp stone blades. They left behind blades, beads, bone tools, and burial
sites—the “behavioral B’s” that anthropologists consider to be the signposts of
behaviorally modern humans. Those kinds of artifacts are typically found in
cultures that possess art, music, myths, and even jokes.

Sadly, there are
no extant Cro-Magnon jokes. I guess you had to be there.